None.
Not Applicable.
Not Applicable.
1. Field of the Invention
The present invention is in the field of adjustable ergonomic supports for seats, especially automobile seats.
2. Related Art
A variety of adjustable ergonomic supports for seating are known. These systems involve movement of an ergonomic support towards and away from the seat occupant in order to support various portions of the seat occupant""s body. Many such ergonomic support devices, especially lumbar supports, also move vertically, so that apex of a lumbar supporting arch may be adjusted up and down so that the supports may be custom adjusted to particular individuals spine.
Such lumbar supports may be roughly divided into four classes. There is an arching basket type, see, e.g., U.S. Pat. No. 5,498,063; a push paddle type see, e.g., U.S. patent application Ser. No. 09/798,657; a tensioning strap type, see, e.g., U.S. Pat. No. 5,769,490; and pneumatic systems, see, e.g., U.S. Pat. No. 5,637,076, all incorporated by reference herein. All of these various types may be mounted on vertical slides so that they can be adjusted vertically. It is common for arching pressure surface type lumbar supports to be mounted on vertical guide rods. A pressure surface may be flexed or bowed outwards to provide a lumbar support, generally through the application of traction via a cable. The release of cable traction allows the natural bias of the pressure surface, usually stamped metal or molded plastic, to flatten it into a rest position, which action is augmented by the weight of the seat occupant.
There is not any natural bias or external force that helps the arching pressure surface type lumbar support to move in either vertical direction however. Prior art lumbar supports have achieved vertical movement of the arching pressure surface by biasing it towards a rest position, usually a bottom position, with springs. Vertical movement into a higher position has been achieved by attaching a single traction cable to the arching pressure surface. This mechanism requires a traction cable and an actuator for applying traction to the cable that are of a heavy enough gauge and great enough power can overcome the opposing tensioning force of the spring.
In the lumbar support field, as in auto parts in general, there is a continuing need for reducing costs, complexity and expense and also a continuing need for increasing durability, simplicity, compactness and ease of assembly. There is a need in the lumbar support arts for achieving vertical movement for a lumbar support in a manner that avoids the expense, complexity and weight of prior art single cable and spring apparatuses.
The present invention is a two cable system for vertical movement of a lumbar support.
In an arching pressure surface lumbar support with vertical adjustment capability, an arching pressure surface is mounted on vertical guide rails so that the entire pressure surface may slide vertically on the rails, either when the pressure surface is flat or bowed outwards to provide lumbar support. At one end of the pressure surface a traction cable is disposed to pull the pressure surface upwards. Another end of a traction cable is disposed to pull the pressure surface downwards.
In alternative embodiments, two separate traction cables may be used, or a single traction cable disposed in a loop fashion may be used.
Traction cables, such as the commonly used Bowden cable, are coaxial mechanical devices having a conduit or sleeve inside of which a wire is disposed to slide axially. In all embodiments, an end of a Bowden cable sleeve (or wire) is mounted to a fixed, non-moving support bracket and an end of the Bowden cable wire (or sleeve) is fixed to the arching pressure surface. An actuator at the other end of the Bowden cable applies traction, drawing the wire into the cable. At the first end of the Bowden cable the wire, now under traction, draws the pressure surface to which it is attached towards the fixed mounting of the Bowden cable sleeve end. The pressure surface slides vertically along the guide rails. The second Bowden cable sleeve end is also fixedly mounted to a bracket and a second Bowden cable wire end is also attached to the pressure surface and disposed to pull the pressure surface in the opposite vertical direction when tension is applied to the second Bowden cable wire. The fixed mounting of the Bowden cable sleeves may be on opposite vertical ends of the pressure surface. Alternatively, the fixed mounting of the Bowden cable sleeves may be on the same vertical end of the arching pressure surface, with the direction of one end of one of them redirected 180xc2x0 by a pulley or other deflection apparatus fixedly mounted on the opposite end of the lumbar support. The two Bowden cable sleeve ends and wire ends may be opposite ends of a single Bowden cable, with an actuator remotely engaged thereto in order to pull it in either direction. Alternatively, two separate Bowden cables may be used. Two separate Bowden cables may be driven by a single actuator capable of bi-directional action, or by two separate actuators.